Filters feedback messages displayed during the core update process. The filter is first evaluated after the zip file for the latest version has been downloaded and unzipped. It is evaluated five more times during the process:
1. Before WordPress begins the core upgrade process. 2. Before Maintenance Mode is enabled. 3. Before WordPress begins copying over the necessary files. 4. Before Maintenance Mode is disabled. 5. Before the database is upgraded.
- ( 2.5.0 ) . .
- ( string ) The core update feedback messages. . . .